) as main constituent . ○ ( c ) Acid reacts with metal to form hydrogen gas. ○ ( d ) Acid reacts with carbonates and liberates CO2 gas . ○ ( e ) Blue litmus paper turns red in acid .

OH - ( aq ) ● Sodium hydroxide Sodium ion hydroxide ion ● Example : Sodium hydroxide , Potassium hydroxide , Calcium hydroxide . ● Properties of Alkalis : ○ ( a ) Alkali has bitter taste . ○ ( b ) They are slippery . ○ ( c ) Alkali contains hydroxide ( OH ) as a main constituent . ○ ( d ) Metal oxides are generally alkaline in nature . ● Uses of Alkalis : ○ ( a ) Sodium hydroxide / caustic soda ( NaOH ) is used in preparation of soaps . ○ ( b ) Potassium hydroxide / Potash ( KOH ) is used in preparation of soap and shampoo . ○ ( c ) Calcium hydroxide / lime water is used to prepare lime / used in white washing . ○ ( d ) Magnesium hydroxide ( Mg ( OH ) ₂ ) is used in preparation of Antacids . ( Acidity resistant medicines ) ○ ( e ) Ammonium hydroxide ( NH , OH ) is used in production of fertilizers .

) as the main constituent . ( iii ) Blue litmus turns red in acid . ( iv ) Non metal oxides are generally acidic in nature ( i ) Alkali has bitter taste. ( ii )Alkali molecules contains hydroxide ion ( OH ) as the main constituent . ( iii ) Red litmus turns blue in alkali . ( iv ) Metal oxides are generally alkaline in nature .